Web severing devices in web feeding machines



Nov. 3, 195? w. T. CHODOROWSKI 2,911,132

WEB SEVERING DEV-ICES IN WEB FEEDING MACHINES Filed Nov. 5, 1957 3 Sheets-Sheet, 1

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3 Sheets-Sheet 2 w. 'r. CHODOROWSKI WEB SEVERING DEVICES IN- WEB FEEDING MACHINES Filed Nov. 5, 1957 Nov. 3, 1959 Nov. 3, 1959 2,911,132

wEB SEVERING DEVICES IN WEB FEEDING MACHINES Filed Nov. 5, 1957 W. T. C HODOROWSKI 3 Sheets-Sheet 3 United States Patent G WEB SEVERING DEVICES IN WEB FEEDING MACHINES Wieslaw Tadeusz Chodorowski, Bristol, England, assignor to Strachan & Henshaw Limited, Whitehall, Bristol, England, a British company Application November '5, 19,51 Serial No. 624,569

Claims priority, application Great Britain November 6, 1956v 3 Claims. (Cl. 225-.-101) This invention relates to web severing means for. use in machines wherein a web, for example, a paper or like web, is fed therethrough.

It is known to provide web severing means comprising a web retarding unit and a web accelerating unit, the two said units being timed to act synchronously when a line of weakening of the web is disposed between the said two units, whereby the web is severed at the said line of weakening by reason of the tension applied by the two units to the portion of the web disposed therebetween.

The object of the present invention is to provide an improved unit which will operate as a web retarding unit or as a web accelerating unit in web severing means of the kind referred to.

According to this invention web severing means, com prising two units for varying the speed of travel of the web through a machine, one of said units operating to retard the said speed of travel of the web and the other said unit operating to accelerate the said speed of travel of the web whereby to sever the web at a position between said units along a previously made line of weakening in the web, is characterised in that at least one of the said units comprises first and second rolls mounted on parallel axes and adapted to co-operate with each other to grip the web therebetween at predetermined intervals of distance along the web, a rotatable carrier having the said first roll mounted rotatably therein with the axes of the said carrier and first roll offset or eccentric relative to each other, an internal gear mounted co-axially with said carrier but rotatable independently of the carrier, a planet gear mounted co-axially with said first roll for fixed rotation therewith, said planet gear being in meshing engagement with said internal gear, the carrier and the second roll being mounted on fixed position axes, the carrier, the first roll and the second roll being so relatively disposed that the periphery of the first roll is disposed in web gripping relationship with the periphery of thev second roil once. during, each revolution of the carrier whereby the web may be gripped therebetween, means for relating the rotation of the carrier to the length of portions which are to be severed from the web, and means for relating the rotation of the second roll and of the internal gear to the speed of travel of the web through the machine.

One form of the invention is illustrated in the accompanying drawings, wherein:

Fig. 1 is a diagrammatic elevation of a machine for forming a web of paper into tubed lengths for subsequent formation into paper bags.

Fig. 2 is a sectional side elevation of a web retarding or accelerating unit, and

Fig. 3 is a diagrammatic end elevation of a said unit.

In the machine illustrated in Fig. 1, a' web 11 of paper is fed from a reel 12 to a device 13 which applies a line of perforations across the web, the successive lines of perforations being disposed at intervals along the web equal to the desired length of the tube portions for forming into bags. The perforated web then travels on to a 2 seam-pasting device 14 which applies a line of adhesive longitudinally along the web. The perforated and pasted web then travels onto a tubing device 15 where the web is formed into a tube. Draw rolls 16 draw the web, which is in the form of a tube when it reaches the said rolls, through the machine and feed the tube to the severing device 17 where the tube is severed, at the line of weakening provided by the perforations, into tube portions which are then discharged. by a discharge unit 18 on to a conveyor 19.

The machine is driven by a common drive means divided into a first branch drive controlling the frequency of engagement of the perforating device 13 with the web 11, that is, controlling the length of the tube portions for forming into bags, and a second branch drive controlling the speed of the draw rolls 16, that is, the speed of travel of the tube. The two branch drives are provided with means for speed variation so as to be independently adjustable but in any one tube portion setting the ratio between frequency of engagement of the perforating device 13 and the speed or" travel of the tube is of course constant.

In the severing device 17 the tube is led in succession through a tube retarding unit 20 adapted to periodically retard the travel of the tube, and a tube accelerating unit 21 adapted to periodically accelerate the travel of the tube. The units 2i) and 21 are spaced apart so that they can act individually on two successive tube portions, and

the units are timed to act simultaneously on the tube when the perforations between two tube portions lie between the said units, whereby the accelerating unit 21 causes the tube portion on which it acts to be severed at the perforations from the tube portion acted upon by the retarding unit 20.

The retarding unit 20 (Figs. 2 and 3) comprises an upper roll 22 and a lower roll 23, which are parallel to each other and are adapted periodically to grip the tubed Web 11. between them. The tubed web 11 travels in the direction indicated by the arrow heads. thereon in Fig. 3,.

The lower roll 23 is rotated in the. clockwise direction, Fig. 3, about a fixed axis 29 positioned for the said roll to make light circumferential contact with the underside of the tubed web 11. The roll 23 is driven from the drive to the draw rolls 16 of the machine, through, for example, gears24 and 25, so that the circumferential speed of the roll 23, in the example, is approximately 5% less than the speed of travel of the. tubed Web prior to reaching the unit 20.

The upper roll 22 is mounted rotatably in a rotatable carrier 26, the axis 27 of the roll 22 being offset or eccentrically disposed relative to the axis, 28- of the carrier 26.. Consequently, the roll 22 will be carried in a circular path around the axis 28 as the carrier 26 rotates. The axis 28 of the carrier 26 is disposed substantially vertically above the axis 29 of the lower roll 23, and is so positioned that the periphery of the upper roll 22 makes contact with the upper side of the tubed web 11 once during each revolution of the carrier 26 whereby the tubed web 11 is gripped momentarily between the rolls 22 and 23. The carrier 26 is rotated in the anti-clockwise direction, Fig. 3, through gears 30 and 31 from the drive of the perforating unit 13 in such manner that the carrier rotates once while the tubed web 11 travels the distance between two successive lines of perforations, that is, the length of one tube portion.

An internally toothed gear 32 is formed in a ring 33 which is mounted for rotation in an anti-clockwise direction, Fig. 3, about an axis which is aligned with the axis 23 of the carrier 26. The pitch circle diameter of the internal gear 32 is equal to the maximum diameter of the path of the roll 22 around the axis 28.

The upper roll 22 has secured to it, at one end thereof,

a toothed gear 34 whose pitch circle diameter is equalto the diameter of said roll 22. The gear 34 meshes With the internal gear 32. Consequently, the roll 22 will have a planetary motion when the carrier 26 rotates.

The speed of engagement of the upper roll 22 with the tubed Web 11 is arranged to be the same as that of the lower roll 23, and since the diameter of the upper roll 22 is equal to the pitch circle diameter of the planet gear 34 the engagement speed of the upper roll 22 with the web 11 is entirely controlled by the speed of the internal gear 32. The engagement speed or" the upper I'Oii 22 is understood to be the speed which the circumference of that roll has at the point of contact with the tubed web 11 by virtue of the compound motion produced by the carrier 26 and the internal gear 32. The engagement speed of the lower roll 23 is, of course, simply the carcumferential speed of the lower roll. Since the engagement speeds of the upper and lower rolls 23 and 22 are related to the speed of travel of the tubed web 11, the internal gear 32 and the lower roll 23 are geared to the draw rolls 16; for example, the internal gear 32 may be driven through gears 24, 35 and 36, the gear 24 also being concerned in the drive to the roll 23.

The length of the portions into which the tubed web 11 is severed may be varied by changing the distance be tween successive lines of weakening, that is, the lines of pelforations, and correspondingly changing the speed of rotation of the carrier 26 without affecting the engagement speed of the rolls with the web.

It will be appreciated that any variation of the speed of rotation of the carrier 26 in order to accommodate said speed to a variation in the length of the bag portions which are to be cut the tubed web will have no eifect upon the engagement speed of the upper roll 22, because the said engagement speed is controlled by the speed of rotation of the internal gear 32.

The accelerating unit 21 is constructed in the same manner as the retarding unit 28, but the engagement speeds of the upper and lower rolls of the accelerating unit are arranged to be, for example, 20% faster than the speed of travel of the tubed web 11 prior to the web reaching the retarding unit 26 Thus the accelerating unit 21 grips and severs the tube portion on which it acts away from the tube portion acted upon by the retarding unit 20 and delivers the severed tube portion to the discharge unit 18. It will be appreciated that at the moment the tubed web is gripped between the rolls 22 and 23 of the two units 20 and 21, the speed of travel of the web is retarded by the unit 20 and simultaneously increased by the unit 21, thus causing the web to be severed across the line of weakening provided by the perforations therein.

The device is particularly suitable for use in connection with multi-wall tubing produced from a plurality of webs individually perforated prior to being collectively fed through the tube forming device. The position of 4. the lower roll 23 of the retarding unit 20 and of the accelerating unit 21 may be adjustable vertically to accommodate variations in the thickness of the tubed web.

It will be obvious that two units according to the invention may be used to provide the retarding and accelcrating units, or only one unit according to the invention may be used to provide the retarding or the accelerating unit, the other unit being provided by any other known means.

What I claim and desire to secure by Letters Patent is:

l. Web severing means, comprising two units for varying the speed of travel of a web through a machine, one of the said units being a retarding unit operating to retard the said speed of travel of the web and the other of the said units being an accelerating unit operating to accelerate the said speed of travel of the web to a speed greater than that efifected by the retarding unit whereby to sever the web at a position between said units along a previously made line of weakening in the web, at least one of the said units comprising first and second rolls mounted on parallel axes and adapted to co-operate with each other to grip the web therebetween at predetermined intervals of distance along the web, a rotatable carrier having the said first roll mounted rotatably therein with the axes of the said carrier and first roll eccentric relative to each other, an internal gear mounted co-axially with said carrier but rotatable independently of the carrier, a planet gear mounted co-axially with said first roll for fixed rotation therewith, said planet gear being in meshing engagement with said internal gear, the carrier and the second roll being mounted on fixed position axes, the carrier, the first roll and the second roll being so relatively disposed that the periphery of the first roll is disposed in web gripping relationship with the periphery of the second roll once during each revolution of the carrier whereby the web may be gripped therebetween, means for relating the rotation of the carrier to the length of portions which are to be severed from the web, and means for relating the rotation of the second roll and of the internal gear to the speed of travel of the web through the machine.

2. Web severing means according to claim 1, wherein said first and second rolls are part of the retarding unit, and the engagement speeds of the said first and second rolls are equal to each other and are less than the speed of travel of the web through the machine.

3. Web severing means according to claim 1, wherein said first and second rolls are parts of the accelerating unit, and the engagement speeds of the said first and second rolls are equal to each other and are greater than the speed of travel of the web through the machine.

Sherman Feb. 3, 1951 Sandberg et a1. May 26, 1953 

